With increasing development of high technology industries, computers are widely used in our daily lives, or otherwise employed for working or amusement purposes. Among the peripheral devices of the computer systems, keyboard devices are essential bridges between the users and the computer systems. Recently, keyboard devices have experienced great growth and are now rapidly gaining in popularity.
Conventionally, when one or more keys are depressed, corresponding characters, numbers or signs are inputted into the computer system. Due to the amazing power of computer systems, computer systems are developed to have various functions. For example, the computer systems are widely used for playing multimedia files or linking to Internet. Under this circumstance, the conventional function of inputting characters by the keyboard device is not satisfied. For helping the user well operate the computer, many novel keyboard devices with expanded functions are developed in views of humanization and user-friendliness. An example of the novel keyboard devices includes a keyboard device with hot keys. A hot key is a key or a set of keys that performs a predefined function. The hot keys of the keyboard device include but are not limited to sound volume hot keys, Web browser hot keys, and the like.
FIG. 1 is a schematic perspective view illustrating a conventional keyboard device. As shown in FIG. 1, the keyboard device 100 comprises a base 101, a touch panel 102, an upper cover 103 and a plurality of keys 104. These keys 104 are mounted on the base 101 and protruded through the upper cover 103. When one or more keys 104 are depressed, corresponding characters, numbers or signs are inputted into the computer system. The upper cover 103 has an opening 1031 for receiving the touch panel 102 and exposing the touch panel 102 to the upper cover 103. The touch panel 102 has a hot key function. When the user touches the touch panel 102, a predefined function (e.g. a sound volume control function) is performed.
FIG. 2 is a schematic perspective view illustrating the inner portion of the conventional keyboard device shown in FIG. 1. The keyboard device 100 comprises the base 101, the plurality of keys 104, a main circuit board 105 and a touching circuit board 106. Within the keyboard device 100, the main circuit board 105 is mounted on the base 101. The main circuit board 105 includes electronic components and electrical traces required for operating the keyboard device 100. The touching circuit board 106 is mounted on the base 101. The touch panel 102 is received in the opening 1031 of the upper cover 103 (as shown in FIG. 1). After the upper cover 103 is placed on the base 101, the touch panel 102 is disposed on the position corresponding to the touching circuit board 106. As shown in FIG. 1, the touch panel 102 is a draggable strip panel made of polycarbonate (PC).
As shown in FIGS. 1 and 2, the hot key function of the keyboard device 100 is implemented by the touch panel 102. The operation of executing the hot key function will be illustrated in more details as follows.
The finger of the user is an electrical conductor which has stored electrons. The touch panel 102 is disposed on the position corresponding to the touching circuit board 106. When a finger of the user touches the touch panel 102, the touch panel 102 is contacted with the touching circuit board 106 and thus a capacitive effect is generated between the touching circuit board 106 and the user's finger (conductor). Due to the capacitive effect, the capacitance of the touching circuit board 106 under the touch region is increased. As a consequence, the charging and discharging time for the touching circuit board 106 is extended in comparison with the situation that the touch panel 102 is not touched by the finger. The magnitude of the charging and discharging time may be used to discriminate whether the touch panel 102 is touched by the finger or not. In a case that the touch panel 102 is a draggable strip panel for adjusting the sound volume of the computer system, a touch region on the touch panel 102 is sensed by the touching circuit board 106 and defined as a datum point when the user's finger touches the touch region. After the touch region is touched by the user's finger, the user's finger may be moved on the touch panel 102 to adjust the volume sound. For example, if the user's finger is placed on the touch panel 102 and then moved upwardly, the volume sound will be augmented. Whereas, if the user's finger is placed on the touch panel 102 and then moved downwardly, the volume sound will be lessened. As a consequence, the touch panel 102 of the keyboard device 100 can be used to execute the volume sound control function without the need of the volume sound control program.
The dragging action on the touch panel 102 is controlled by the touching circuit board 106. The touching circuit board 106 will execute the instructions corresponding to the finger gestures. The capacitive effect generated when the user's finger is placed on the touch region is distinguished from the capacitive effect generated when the user's finger is moved. As known, complicated algorithm is required to firstly discriminate the touch region of the touch panel 102 where the user's finger is placed and then discriminate the dragging action on the touch panel 102. For implementing the complicated algorithm, the electronic components and associated circuitry layout on the touching circuit board 106 become complicated. Under this circumstance, a bulky touching circuit board 106 is necessary. The complicated circuitry layout is not cost-effective.
Therefore, there is a need of providing a keyboard device with reduced cost.